Objective  To investigate the application of DNA ploidy analysis combined with cell immunohistochemistry in secondary electroresection of bladder tumors.Methods  A total of 48 patients with secondary electrotomy for urothelial carcinoma admitted to Shibei hospital of Jing′an district in Shanghai from March 2017 to September 2020 were included in the observation group, another 53 hematuria patients were included in the control group, both groups were examined by DNA multiplication and immunohistochemistry in urine exfoliated cells.Results  The positive rate of abnormal DNA ploidy analysis was 18.75% (9/48) in the observation group, which was higher than 1.89% (1/53) in the control group (P<0.01). The positive rate of abnormal immunohistochemistry of urine exudated cells in the observation group was 16.67% (8/48), which was higher than 1.89% (1/53) in the control group (P<0.05). The positive rate of abnormal DNA ploidy analysis for bladder cancer was 75.00%, and the positive rate of urine exudation cell immunohistochemistry was 66.67%(8/12),  all higher than the control group(all was 0)(all P<0.01).Conclusions  The results of DNA ploidy analysis combined with immunohistochemical examinationcan provide the basis for the secondary electrotomy of bladder tumor.